(1) Field of the Invention
This invention relates generally to the control of plant pests and more particularly to the provision of protection against insect damage to seeds and plant parts by the treatment of plant seeds with combinations of pesticides.
(2) Description of the Related Art
The control of insects and related arthropods is of extreme importance to the agricultural industry. Every year, these pests destroy an estimated 15% of agricultural crops in the United States and even more than that in developing countries. Some of this damage occurs in the soil when plant pathogens, insects and other such soil borne pests attack the seed after planting. Much of the rest of the damage is caused by rootworms; plant pathogens that feed upon or otherwise damage the plant roots; and by cutworms, European corn borers, and other pests that feed upon or damage the above ground parts of the plant. General descriptions of the type and mechanisms of attack of pests on agricultural crops are provided by, for example, Metcalf, in Destructive and Useful Insects, (1962); and Agrios, in Plant Pathology, 3rd Ed., Academic Press (1988).
The period during germination of the seed, sprouting and initial growth of the plant is particularly critical because the roots and shoots of the growing plant are small and even a small amount of damage can kill the entire plant. Moreover, some natural plant defenses are not fully developed at this stage and the plant is vulnerable to attack. Not surprisingly, the control of pests that attack the seed and the above ground plant parts during this early stage of plant growth is a well developed area of agriculture.
Currently, the control of pests that attack post emergent crops primarily involves the application of synthetic organic pesticides to the soil, or to the growing plants by foliar spraying. Because of concern about the impact of chemical pesticides on public health and the environment, there has been much effort to reduce the amount of chemical pesticides that are used. A significant portion of this effort has been expended in developing transgenic crops engineered to express insect toxicants from microorganisms. For example, U.S. Pat. No. 5,877,012 to Estruch et al. discloses the cloning and expression of proteins from such organisms as Bacillus, Pseudomonas, Clavibacter and Rhizobium into plants to obtain transgenic plants with resistance to such pests as black cutworms, armyworms, several borers and other insect pests. Publication WO/EP97/07089 by Privalle et al. teaches the transformation of monocotyledons, such as corn, with a recombinant DNA sequence encoding peroxidase for the protection of the plant from feeding by corn borers, earworms and cutworms. Jansens et al., in Crop Sci., 37(5):1616-1624 (1997), reported the production of transgenic corn containing a gene encoding a crystalline protein from Bacillus thuringiensis that controlled both generations of the European corn borer. U.S. Pat. Nos. 5,625,136 and 5,859,336 to Koziel et al. reported that the transformation of corn with a gene from B. thuringiensis that encoded for delta-endotoxins provided the transgenic corn with improved resistance to European corn borer.
A comprehensive report of field trials of transgenic corn that expresses an insecticidal protein from B. thuringiensis has been provided by Armstrong et al., in Crop Science, 35(2):550-557 (1995).
At the present state of plant cellular engineering, however, transgenic crops are typically resistant only to specific pests for that crop, e.g., transgenic corn expressing a Bt toxin against the corn rootworm. It is frequently necessary to apply synthetic pesticides to such transgenic plants to control damage by other pests.
Insecticides such as synthetic pyrethroids, organophosphates and carbamates; fungicides such as azoles and anilopyrimidines; and acaricides such as pyrazoles; and the like, are very effective against certain above ground plant pests when applied at the proper time and with proper procedures. Appropriate pesticides may be applied at the time of planting as surface bands, xe2x80x9cTxe2x80x9d-bands, or in-furrow, but these applications require the additional operation of applying the pesticide at the same time as the seeds are being sown. This complicates the planting operation and the additional equipment required for pesticide application is costly to purchase and requires maintenance and attention during use. Moreover, care must be taken to incorporate the pesticides properly into the topmost soil layer for optimal activity. (See, for example, the application requirements and precautions for use of tefluthrin that are described in the brochure titled Force 3G Insecticide, published by Zeneca Ag Products, Wilmington, Del. (1998)).
The activity of pesticides that have been applied as in-furrow applications at the time of sowing is usually directed to the protection of the seed or the roots of the plant. Some protection against above ground pests such as corn borers has been reported, however, for such treatments with insecticides known to be systemic. Keaster and Fairchild, J. Econ. Entomol., 61(2):367-369 (1968). Since such pesticide chemicals are complex molecules that are expensive to produce, purchase and use, it is desirable that their activity is not diluted or lost by migration away from the desired site of action by moisture seepage or by vaporization.
After the plant has emerged from the soil, foliar spraying of pesticides is most often used to control those pests that attach the shoots and foliage of the plant. However, a foliar spray must be applied at a certain time that coincides with the presence and activity of the pest in order to have the most beneficial effect. Application at this time may be difficult or impossible if, for example, weather conditions limit access to the field. Moreover, the plants must be monitored closely to observe early signs of pest activity in order to apply the pesticide at a time when the pests are most vulnerable.
Synthetic pyrethroids have been found to give excellent control of pests of the order of Lepidoptera, such as cutworms, when applied as foliar spray or as surface-incorporated granules at the time of planting. However, since this class of insecticides has very high toxicity to fish, for example, great care must be taken to limit the runoff of the insecticide from either granules or spray into surface waters. Moreover, any foliar spraying must be done at times when there is little wind, and then only with proper equipment that is carefully monitored during use.
It has also been found in some cases with particular pesticides and application techniques that when two or more of such pesticides are used in particular combination greater efficacy results than when any one of such pesticides is used alone. Such benefits of combining pesticides has been reported for combinations of phosmet with diflubenzuron (U.S. Pat. No. 4,382,927); O-ethyl-O-[4-(methylthio)-phenyl]-S-propyl phosphodithioate and Nxe2x80x2-(4-chloro-o-tolyl)-N,N--dimethylformamidine (U.S. Pat. No. 4,053,595); bacillus thuringiensis and chlordimeform (U.S. Pat. No. 3,937,813); decamethrine and dichlorvos with propoxur, if desired, (U.S. Pat. No. 4,863,909); fenvalerate and phosmet (U.S. Pat. No. 4,263,287); and phosalone and malathion (U.S. Pat. No. 4,064,237). However, each of these combinations was applied directly to the growing plant as described above in the form of sprays or dusts, or applied to the soil around the plant in the form of, for example, granules.
WO9740692 discloses combinations of any one of several oxadiazine derivatives with one of a long list of other insecticides. Although the application mentions that the combinations can be applied to plant propagation material for its protection, as well as to plant shoots and leaves, no examples are provided to demonstrate that any one of the combinations listed is actually efficacious. More pesticide combinations are described in U.S. Pat. Nos. 4,415,561, 5,385,926, 5,972,941 and 5,952,358. However, in the existing art, little or no guidance has been found as methods for predicting which combinations of pesticides will result in such unexpectedly superior efficacy and which combinations will not.
The control of pests by applying insecticides directly to plant seed is well known. For example, U.S. Pat. No. 5,696,144 discloses that the European corn borer caused less feeding damage to corn plants grown from seed treated with a 1-arylpyrazole compound at a rate of 500 g per quintal of seed than control plants grown from untreated seed. In addition, U.S. Pat. No. 5,876,739 to Turnblad et al. (and its parent, U.S. Pat. No. 5,849,320) disclose a method for controlling soil-borne insects which involves treating seeds with a coating containing one or more polymeric binders and an insecticide. This reference provides a list of insecticides that it identifies as candidates for use in this coating and also names a number of potential target insects. However, while the U.S. Pat. No. 5,876,739 patent states that treating corn seed with a coating containing a particular insecticide protects corn roots from damage by the corn rootworm, it does not indicate or otherwise suggest that treatment of corn seed with any particular combinations of insecticides provides the seed or the plant with synergistic protection, or with any other unexpected advantage.
Thus, although the art of protecting the shoots and foliagexe2x80x94as well as the seed and rootsxe2x80x94of a plant from damage by pests has been advancing rapidly, several problems still remain. For example, it would be useful to provide a method for the control of pest damage to shoots and foliage of plants without the requirement of applying a pesticide at the time of sowing the seed, either as a surface incorporated band, or in-furrow, for example, or requiring a later field application of a pesticide during plant growth. It would also be useful if the method for pest control reduced the amount of pesticide that was required to provide a certain level of protection to the plant. Furthermore, it would be useful if such a method could be coupled with the biopesticidal activity of transgenic plants, or with the insecticidal activity of other active materials to provide a broader scope of protection than is provided by the transgenic elements, or the insecticidal actives alone.
Briefly, therefore, the present invention is directed to a novel method for preventing damage by a pest to a seed and/or shoots and foliage of a plant grown from the seed, the method comprising treating the unsown seed with a composition comprising at least one pyrethrin or synthetic pyrethroid and at least one other insecticide selected from the group consisting of an oxadiazine derivative, a chloronicotinyl, a nitroguanidine, a pyrrol, a pyrazone, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate. It is preferred that when the other insecticide is an oxadizine derivative, the pyrethroid is selected from the group consisting of taufluvalinate, flumethrin, trans-cyfluthrin, kadethrin, bioresmethrin, tetramethrin, phenothrin, empenthrin, cyphenothrin, prallethrin, imiprothrin, allethrin and bioallethrin. Seeds that have been treated by this method are also provided.
The invention is also directed to a novel composition for the treatment of unsown seed comprising at least one pyrethrin or synthetic pyrethroid and at least one other insecticide selected from the group consisting of an oxadiazine derivative, a chloronicotinyl, a nitroguanidine, a pyrrol, a pyrazone, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate. It is preferred that when the other insecticide is an oxadizine derivative, the pyrethroid is selected from the group consisting of taufluvalinate, flumethrin, trans-cyfluthrin, kadethrin, bioresmethrin, tetramethrin, phenothrin, empenthrin, cyphenothrin, prallethrin, imiprothrin, allethrin and bioallethrin.
The invention is also directed to a novel method for preventing damage by a pest to a seed and/or shoots and foliage of a plant grown from the seed, the method comprising treating the unsown seed with a composition comprising a nitroguanidine and at least one other insecticide selected from the group consisting of a chloronicotinyl, a pyrrol, a pyrazone, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate. Seeds that have been treated by this method are also provided.
The invention is also directed to a novel composition for treatment of unsown seed, the composition comprising a nitroguanidine and at least one other insecticide selected from the group consisting of a chloronicotinyl, a pyrrol, a pyrazone, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate.
The invention is also directed to a novel seed that is protected against multiple pests comprising a seed having at least one heterologous gene encoding for the expression of a protein that is active against a first pest and, in addition, having adhered thereto a composition comprising at least one pyrethrin or synthetic pyrethroid and at least one other insecticide selected from the group consisting of an oxadiazine derivative, a chloronicotinyl, a nitroguanidine, a pyrrol, a pyrazone, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate, where the composition is present in an amount effective to provide protection to the shoots and foliage of the plant against damage by at least one second pest.
The invention is also directed to a novel method for treating an unsown seed to prevent damage by a pest to the seed and/or shoots and foliage of a plant grown from the seed, the method comprising contacting the unsown seed with a composition comprising at least one pyrethrin or synthetic pyrethroid and at least one other insecticide selected from the group consisting of an oxadiazine derivative, a chloronicotinyl, a nitroguanidine, a pyrrol, a pyrazone, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate, provided that when the other insecticide is an oxadizine derivative, the pyrethroid is selected from the group consisting of taufluvalinate, flumethrin, trans-cyfluthrin, kadethrin, bioresmethrin, tetramethrin, phenothrin, empenthrin, cyphenothrin, prallethrin, imiprothrin, allethrin and bioallethrin.
Among the advantages found to be achieved by the present invention, therefore, may be noted the provision of a method for the control of pest damage to seeds and/or shoots and foliage of plants without the requirement of applying a pesticide at the time of sowing the seed, either as a surface incorporated band, or in-furrow, for example, or requiring a later field application of a pesticide during plant growth; the provision of a method for pest control that reduces the amount of pesticide that is required for the provision of a certain level of protection to the plant; and the provision of method that can be coupled with the biopesticidal activity of transgenic plants to selectively broaden the scope of protection that is provided for the shoots and foliage of the transgenic.
In accordance with the present invention, it has been discovered that treatment of unsown plant seeds with a composition that includes a specific combination of insecticides not only protects the seeds themselves, butxe2x80x94surprisinglyxe2x80x94also provides post-emergent control of pests that feed on or otherwise damage the shoots and/or foliage of the plant. The combination of insecticides that has been found to achieve such results is a combination of a pyrethrin or synthetic pyrethroid as one component, and with another component comprising one or more of certain other insecticides selected from the group consisting of an oxadiazine derivative, a chloronicotinyl, such as imidacloprid, acetamiprid, and nitenpyram; a nitroguanidine; a pyrrol, such as chlorfenapyr; a pyrazole, such as tebufenpyrad; a diacylhydrazine, such as tebufenozide, methoxyfenozide, and halofenozide; a triazole, such as triazamate; a biological/fermentation product, such as avermectin and spinosad; a phenyl pyrazole, such as fipronil; an organophosphate, such as acephate, fenamiphos, diazinon, chlorpyrifos, chlorpyrifon-methyl and malathion; and a carbamate, such as carbaryl, aldicarb, carbofuran, thiodicarb and oxamyl. It is preferred, however, that if the other insecticide is an oxadiazine derivative, the pyrethroid should be selected from the group consisting of taufluvalinate, flumethrin, trans-cyfluthrin, kadethrin, bioresmethrin, tetramethrin, phenothrin, empenthrin, cyphenothrin, prallethrin, imiprothrin, allethrin and bioallethrin.
In preferred embodiments, the combination of the insecticides provides unexpectedly superior protection in that the combination of the insecticides provides a level of protection to the seed and/or the plant that is superior to the level of protection thatxe2x80x94based on the current state of the artxe2x80x94would be predicted from the protection provided by the individual components applied separately. This synergistic activity reduces the total amount of pesticide that is required to provide a certain level of protection. In addition to being more economical to use, the ability to use a reduced amount of pesticide for a given level of protection is advantageous in that seed treatments with reduced amounts of insecticides are less phytotoxic to the seed than when the insecticides are used separately.
Another advantage of the novel treatment is that it can be used with transgenic seeds of the type having a heterologous gene encoding for the expression of a pesticidal protein in the transgenic plant that grows from the seed. Treating such a seed with a pesticide provides the ability to protect against one pest with the transgenic trait and to provide surprisingly enhanced protection against the same pest, and/or to protect against other pests with the subject combination of insecticides.
As used herein, the terms xe2x80x9cpesticidal effectxe2x80x9d and xe2x80x9cpesticidal activityxe2x80x9d mean any direct or indirect action on the target pest that results in reduced feeding damage on the seeds, roots, shoots and foliage of plants grown from treated seeds as compared to plants grown from untreated seeds. The terms xe2x80x9cactive against a (first or second) pestxe2x80x9d, also have the same meaning. Such direct or indirect actions include inducing death of the pest, repelling the pest from the plant seeds, roots, shoots and/or foliage, inhibiting feeding of the pest on, or the laying of its eggs on, the plant seeds, roots, shoots and/or foliage, and inhibiting or preventing reproduction of the pest. The term xe2x80x9cinsecticidal activityxe2x80x9d has the same meaning as pesticidal activity, except it is limited to those instances where the pest is an insect. When the term xe2x80x9cpesticidexe2x80x9d is used herein, it is not meant to include pesticides that are produced by the particular seed or the plant that grows from the particular seed that is treated with the pesticide.
As used herein, the xe2x80x9cshoots and foliagexe2x80x9d of a plant are to be understood to be the shoots, stems, branches, leaves and other appendages of the stems and branches of the plant after the seed has sprouted, but not including the roots of the plant. It is preferable that the shoots and foliage of a plant be understood to be those non-root parts of the plant that have grown from the seed and are located a distance of at least one inch away from the seed from which they emerged (outside the region of the seed), and more preferably, to be the non-root parts of the plant that are at or above the surface of the soil. As used herein, the xe2x80x9cregion of the seedxe2x80x9d is to be understood to be that region within about one inch of the seed.
Pesticides suitable for use in the invention include pyrethrins and synthetic pyrethroids; oxadizine derivatives; chloronicotinyls; nitroguanidine derivatives; triazoles; organophosphates; pyrrols; pyrazoles; phenyl pyrazoles; diacylhydrazines; biological/fermentation products; and carbamates. Further information about pesticides of the types listed above can be found in The Pesticide Manual, 11th Ed., C. D. S. Tomlin, Ed., British Crop Protection Council, Farnham, Surry, UK (1997).
Pyrethroids that are useful in the present composition include pyrethrins and synthetic pyrethroids. The pyrethrins that are preferred for use in the present method include, without limitation, 2-allyl-4-hydroxy-3-methyl-2-cyclopenten-1-one ester of 2,2-dimethyl-3-(2-methyl propenyl)-cyclopropane carboxylic acid, and/or (2-methyl-1-propenyl)-2-methoxy-4-oxo-3-(2 propenyl)-2-cyclopenten-1-yl ester and mixtures of cis and trans isomers thereof (Chemical Abstracts Service Registry Number (xe2x80x9cCAS RNxe2x80x9d) 8003-34-7).
Synthetic pyrethroids that are preferred for use in the present invention include (s)-cyano(3-phenoxyphenyl)methyl 4-chloro alpha (I-methylethyl)benzeneacetate (fenvalerate; CAS RN 51630-58-1); (S)-cyano (3-phenoxyphenyl) methyl (S)-4-chloro-alpha-(1-methylethyl) benzeneacetate (esfenvalerate; CAS RN 66230-04-4); (3-phenoxyphenyl)-methyl(+)cis-trans-3-(2,2-dichoroethenyl)-2,2-dimethylcyclopropanecarboxylate (permethrin; CAS RN 52645-53-1); (xc2x1) alpha-cyano-(3-phenoxyphenyl) methyl(+)-cis,trans-3-(2,2-dichloroethenyl)-2,2-dimethyl-cyclopropane carboxylate (cypermethrin; CAS RN 52315-07-8); (beta-cypermethrin; CAS RN 65731-84-2); (theta cypermethrin; CAS RN 71697-59-1); S-cyano (3-phenoxyphenyl) methyl (xc2x1) cis/trans 3-(2,2-dichloroethenyl) 2,2-dimethylcyclopropane carboxylate (zeta-cypermethrin; CAS RN 52315-07-8); (s)-alpha-cyano-3-phenoxybenzyl (IR,3R)-3-(2,2-dibromovinyl)-2,2-dimethyl cyclopropanecarboxylate (deltamethrin; CAS RN 52918-63-5); alpha-cyano-3-phenoxybenzyl 2,2,3,3,-tetramethyl cyclopropoanecarboxylate (fenpropathrin; CAS RN 64257-84-7); (RS)-alpha-cyano-3-phenoxybenzyl(R)-2-[2-chloro-4-(trifluoromethyl)anilino]-3-methylbutanoate (tau-fluvalinate; CAS RN 102851-06-9); (2,3,5,6-tetrafluoro-4-methylphenyl)-methyl-(1 alpha, 3 alpha)-(Z)-(xc2x1)-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylate (tefluthrin; CAS RN 79538-32-2); (xc2x1)-cyano (3-phenoxyphenyl) methyl (xc2x1)-4-(difluoromethoxy)-alpha-(1-methyl ethyl) benzeneacetate (flucythrinate; CAS RN 70124-77-5); cyano(4-fluoro-3-phenoxyphenyl)methyl 3-[2-chloro-2-(4-chlorophenyl)ethenyl]-2,2-dimethylcyclopropanecarboxylate (flumethrin; CAS RN 69770-45-2); cyano(4-fluoro-3-phenoxyphenyl) methyl 3-(2,2-dichloroethenyl)-2,2-dimethyl-cyclopropanedarboxylate (cyfluthrin; CAS RN 68359-37-5); (beta cyfluthrin; CAS RN 68359-37-5); (transfluthrin; CAS RN 118712-89-3); (S)-alpha-cyano-3-phenoxybenzyl(Z)-(IR-cis)-2,2-dimethyl-3-[2-(2,2,2-trifluoro-trifluoromethyl-ethoxycarbonyl)vinyl]cyclopropane carboxylate (acrinathrin; CAS RN 101007-06-1); (IR cis) S and (IS cis) R enantiomer isomer pair of alpha-cyano-3-phenoxybenzyl-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate (alpha-cypermethrin; CAS RN 67375-30-8); [IR,3S)3(1xe2x80x2RS)(1xe2x80x2,2xe2x80x2,2xe2x80x2,2xe2x80x2-tetrabromoethyl)]-2,2-dimethyl cyclopropanecarboxylic acid (s)-alpha-cyano-3-phenoxybenzyl ester (tralomethrin; CAS RN 66841-25-6); cyano-(3-phenoxyphenyl) methyl 2,2-dichloro-1-(4-ethoxyphenyl)cyclopropane carboxylate (cycloprothrin; CAS RN 63935-38-6); [1xcex1, 3xcex1(Z)]-(xc2x1)-cyano-(3-phenoxyphenyl)methyl 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-cimethylcyclopropanecarboxylate (cyhalothrin; CAS RN 68085-85-8); [1 alpha (s), 3 alpha(z)]-cyano(3-phenoxyphenyl) methyl-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropane carboxylate (lambda cyhalothrin; CAS RN 91465-08-6); (2-methyl [1,1xe2x80x2-biphenyl]-3-yl) methyl 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl-cyclopropanecarboxylate (bifenthrin; CAS RN 82657-04-3); 5-1-benzyl-3-furylmethyl-d-cis(1R,3S,E)2,2-dimethyl-3-(2-oxo,-2,2,4,5 tetrahydro thiophenylidenemethyl)cyclopropane carboxylate (kadethrin, RU15525; CAS RN 58769-20-3); [5-(phenyl methyl)-3-furanyl]-3-furanyl 2,2-dimethyl-3-(2-methyl-1-propenyl) cyclopropane carboxylate (resmethrin; CAS RN 10453-86-8); (1R-trans)-[5-(phenylmethyl)-3-furanyl]methyl 2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylate (bioresmethrin; CAS RN 28434-01-7); 3,4,5,6-tetrahydro-phthalimidomethyl-(IRS)-cis-trans-chrysanthemate (tetramethrin; CAS RN 7696-12-0); 3-phenoxybenzyl-d,I-cis,trans 2,2-dimethyl-3-(2-methylpropenyl) cyclopropane carboxylate (phenothrin; CAS RN 26002-80-2); (empenthrin; CAS RN 54406-48-3); (cyphenothrin; CAS RN 39515-40-7); (prallethrin; CAS RN 23031-36-9); (imiprothrin; CAS RN 72963-72-5); (RS)-3-allyl-2-methyl-4-oxcyclopent-2-enyl-(1A,3R; 1R,3S)-2,2-dimethyl-3-(2-methylprop-1-enyl) cyclopropane carboxylate (allethrin; CAS RN 584-79-2); (bioallethrin; CAS RN 584-79-2); and (ZXI8901; CAS RN 160791-64-0). It is believed that mixtures of one or more of the aforementioned synthetic pyrethroids can also be used in the present invention.
In one embodiment of the present invention, particularly preferred synthetic pyrethroids are tefluthrin, lambda cyhalothrin, bifenthrin, permethrin and cyfluthrin. Even more preferred synthetic pyrethroids are tefluthrin and lambda cyhalothrin.
In another embodiment of the invention xe2x80x94where an oxadiazine derivative is used as one of the combination of insecticidesxe2x80x94the preferred synthetic pyrethroid is selected from the group consisting of taufluvalinate, flumethrin, trans-cyfluthrin, kadethrin, bioresmethrin, tetramethrin, phenothrin, empenthrin, cyphenothrin, prallethrin, imiprothrin, allethrin and bioallethrin.
The pyrethrins and synthetic pyrethroids that are useful in the present compositions can be of any grade or purity that pass in the trade as pyrethrins and synthetic pyrethroids. Other materials that accompany the pyrethrins and synthetic pyrethroids in commercial preparations as impurities can be tolerated in the subject compositions, as long as such other materials do not destabilize the composition or significantly reduce or destroy the activity of any of the insecticide components against the target pest. One of ordinary skill in the art of the production of insecticides can readily identify those impurities that can be tolerated and those that cannot.
Insecticides that are oxadiazine derivatives are useful as one of the components of the subject composition. Oxadizine derivatives that are preferred for use in the present invention include 5-(2-chloropyrid-5-ylmethyl)-3-methyl-4-nitroiminoperhydro-1,3,5-oxadiazine; 3-methyl-4-nitroimino-5-(1-oxido-3-pyridinomethyl) perhydro-1,3,5-oxadiazine; 5-(2-chloro-1-oxido-5-pyridiniomethyl)-3-methyl-4-nitroiminoperhydro-1,3,5-oxidiazine; and 3-methyl-5-(2-methylpyrid-5-ylmethyl)-4-nitroiminoperhydro-1,3,5-oxadiazine.
Chloronicotinyl insecticides are also useful as one of the components of the subject composition. Chloronicotinyls that are preferred for use in the subject composition include acetamiprid ((E)-N-[(6-chloro-3-pyridinyl)methyl]-Nxe2x80x2-cyano-N-methyleneimidamide; CAS RN 135410-20-7); imidacloprid (1-[(6-chloro-3-pyridinyl)methol]-N-nitro-2-imidazolidinimime; CAS RN 138261-41-3); and nitenpyram (N-[(6-chloro-3-pyridinyl)methyl]-N-ethyl-Nxe2x80x2-methyl-2-nitro-1,1-ethenediamine; CAS RN 120738-89-8).
Nitroguanidine insecticides are useful as one of the components of the present combination. Nitroguanidines that are preferred for use in the present invention include MTI 446 (nidinotefuran).
Pyrrols, pyrazoles and phenyl pyrazoles that are useful in the present composition include those that are described in U.S. Pat. No. 5,952,358. Preferred pyrazoles include chlorfenapyr (4-bromo-2-(4-chlorophenyl)-1-ethoxymethyl-5-trifluoromethylpyrrole-3-carbonitrile; CAS RN 122453-73-0); fenpyroximate ((E)-1,1-dimethylethyl-4[[[[(1,3-dimethyl-5-phenoxy-1H-pyrazole-4-yl)methylene]amino]oxy]methyl]benzoate; CAS RN 111812-58-9); and tebufenpyrad (4-chloro-N[[4-1,1-dimethylethyl)phenyl]methyl]-3-ethyl-1-methyl-1H-pyrazole-5-carboxamide; CAS RN 119168-77-3). A preferred phenyl pyrazole is fipronil (5-amino-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(1R,S)-(trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile; CAS RN 120068-37-3).
Diacylhydrazines that are useful in the present invention include halofenozide (4-chlorobenzoate-2-benzoyl-2-(1,1-dimethylethyl)-hydrazide; CAS RN 112226-61-6); methoxyfenozide (RH-2485; N-tert-butyl-Nxe2x80x2-(3-methoxy-o-toluoyl)-3,5-xylohydrazide; CAS RN 161050-58-4); and tebufenozide (3,5-dimethylbenzoic acid 1-(1,1-dimethylethyl)-2,(4-ethylbenzoyl)hydrazide; CAS RN 112410-23-8).
Triazoles, such as amitrole (CAS RN 61-82-5) and triazamate are useful in the composition of the present invention. A preferred triazole is triazamate (ethyl [[1-[(dimethylamino)carbonyl]-3-(1,1-dimethylethyl)-1H-1,2,4-triazol-5-yl]thio]acetate; CAS RN 112143-82-5).
Biological/fermentation products, such as avermectin (abamectin; CAS RN 71751-41-2) and spinosad (XDE-105, CAS RN 131929-60-7) are useful in the present composition.
Organophosphate insecticides are also useful as one of the components of the composition of the present invention. Preferred organophophate insecticides include acephate (CAS RN 30560-19-1); chlorpyrifos (CAS RN 2921-88-2); chlorpyrifos-methyl (CAS RN 5598-13-0); diazinon (CAS RN 333-41-5); fenamiphos (CAS RN 22224-92-6); and malathion (CAS RN 121-75-5).
In addition, carbamate insecticides are useful in the subject composition. Preferred carbamate insecticides are aldicarb (CAS RN 116-06-3); carbaryl (CAS RN 63-25-2); carbofuran (CAS RN 1563-66-2); oxamyl (CAS RN 23135-22-0) and thiodicarb (CAS RN 59669-26-0).
When an insecticide is described herein, it is to be understood that the description is intended to include salt forms of the insecticide as well as any isomeric and/or tautomeric form of the insecticide that exhibits the same insecticidal activity as the form of the insecticide that is described.
One embodiment of this invention comprises treating a seed with a composition comprising at least one pyrethrin or synthetic pyrethroid and at least one other insecticide selected from the group consisting of a chloronicotinyl, a nitroguanidine, a pyrrol, a pyrazole, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate. The treatment is applied to the seed prior to sowing the seed so that the sowing operation is simplified. In this manner, seeds can be treated, for example, at a central location and then dispersed for planting. This permits the person who plants the seeds to avoid the handling and use of insecticidesxe2x80x94some of which can be toxicxe2x80x94and to merely handle and plant the treated seeds in a manner that is conventional for regular untreated seeds. It is preferred, in some combinations that at least one of the pyrethroid and the other insecticide is a systemic insecticide.
In this embodiment, a seed can be treated with any one of the combinations of insecticides that are shown in Table 1.
When the other insecticide is an oxadiazine derivative, it has been found that it is preferred that the at least one pyrethroid be selected from the group consisting of taufluvalinate, flumethrin, trans-cyfluthrin, kadethrin, bioresmethrin, tetramethrin, phenothrin, cyphenothrin, prallethrin, imiprothrin, allethrin and
In another embodiment, the subject method comprises treating a seed prior to sowing with a composition comprising a nitroguanidine and at least one other insecticide selected from the group consisting of a chloronicotinyl, a pyrrol, a pyrazone, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate.
It has also been found that a transgenic seed can be protected against multiple pests when the seed has at least one heterologous gene encoding for the expression of a protein that is active against a first pest and, in addition, having adhered thereto a composition comprising at least one pyrethrin or synthetic pyrethroid and at least one other insecticide selected from the group consisting of an oxadiazine derivative, a chloronicotinyl, a nitroguanidine, a pyrrol, a pyrazone, a diacylhydrazine, a triazole, a biological/fermentation product, a phenyl pyrazole, an organophosphate and a carbamate. It is preferred that the composition containing the synergistic combination of insecticides is present in an amount effective to provide protection to the shoots and foliage of the plant against damage by at least one second pest.
When the transgenic seed has at least one heterologous gene encoding for the expression of a protein that is active against a first pest, the seed can be treated with a combination of insecticides, which combination has activity against at least one second pest. The present method can be used when the first pest and the second pest are the same, for the purpose, for example, to obtain effective control of a particularly resistant or highly damaging pest. But in a separate embodiment, the transgenic trait protects the seed and/or plant from a first pest and the composition of the combination of insecticides is selected to control a second pest that is different from the first pest. This method is particularly advantageous when an expressed transgenic gene provides a gene product that can protect a transgenic plant from one pest, but has no activity against a second, different pest. In this case, a combination of insecticides of the present invention can be selected that has activity against the second pest, thus providing the seed and plant with protection from both pests. By way of explanation, when a xe2x80x9cfirstxe2x80x9d pest and a xe2x80x9csecondxe2x80x9d pest are referred to herein, it should be understood that each of the terms can include only one pest, or can include two or more pests.
It is contemplated that the present method can be used to protect the seeds, roots and/or the above-ground parts of field, forage, plantation, glasshouse, orchard or vineyard crops, ornamentals, plantation or forest trees. The seeds that are useful in the present invention can be the seeds of any species of plant. However, they are preferably the seeds of plant species that are agronomically important. In particular, the seeds can be of corn, peanut, canola/rapeseed, soybean, curcubits, crucifers, cotton, beets, rice, sorghum, sugar beet, wheat, barley, rye, sunflower, tomato, sugarcane, tobacco, oats, as well as other vegetable and leaf crops. It is preferred that the seed be corn, soybeans, or cotton seed; and more preferred that the seeds be corn seeds.
In one embodiment of the invention, as mentioned above, the seed is a transgenic seed from which a transgenic plant can grow. The transgenic seed of the present invention is engineered to express a desirable characteristic and, in particular, to have at least one heterologous gene encoding for the expression of a protein that is pesticidally active and, in particular, has insecticidal activity. The heterologous gene in the transgenic seeds of the present invention can be derived from a microorganism such as Bacillus, Rhizobium, Pseudomonas, Serratia, Trichoderma, Clavibacter, Glomus, Gliocladium and mycorrhizal fungi. In particular, it is believed that the present method would be especially beneficial when the heterologous gene is one that is derived from a Bacillus sp. microorganism and the protein is active against corn rootworm. It is also believed that the present method would be especially beneficial when the heterologous gene is one that is derived from a Bacillus sp. microorganism and the protein is active against European corn borer. A preferred Bacillus sp. microorganism is Bacillus thuringiensis. It is particularly preferred when the heterologous gene encodes a modified Cry3Bb delta-endotoxin derived from Bacillus thuringiensis, as disclosed, for example, in U.S. Pat. No. 6,063,597.
The target pest for the present invention is an adult or larvae of any insect or other pest that feeds on the seed, roots and/or shoots and foliage of the plant that is to be protected by the subject method. Such pests include but are not limited to:
from the order Lepidoptera, for example,
Acleris spp., Adoxophyes spp., Aegeria spp., Agrotis spp., Alabama argillaceae, Amylois spp., Anticarsia gemmatalis, Archips spp, Argyrotaenia spp., Autographa spp., Busseola fusca, Cadra cautella, Carposina nipponensis, Chilo spp., Choristoneura spp., Clysia ambiguella, Cnaphalocrocis spp., Cnephasia spp., Cochylis spp., Coleophora spp., Crocidolomia binotalis, Cryptophlebia leucotreta, Cydia spp., Diatraea spp., Diparopsis castanea, Earias spp., Ephestia spp., Eucosma spp., Eupoecilia ambiguella, Euproctis spp., Euxoa spp., Grapholita spp., Hedya nubiferana, Heliothis spp., Hellula undalis, Hyphantria cunea, Keiferia lycopersicella, Leucoptera scitella, Lithocollethis spp., Lobesia botrana, Lymantria spp., Lyonetia spp., Malacosoma spp., Mamestra brassicae, Manduca sexta, Operophtera spp., Ostrinia Nubilalis, Pammene spp., Pandemis spp., Panolis flammea, Pectinophora gossypiella, Phthorimaea operculella, Pieris rapae, Pieris spp., Plutella xylostella, Prays spp., Scirpophaga spp., Sesamia spp., Sparganothis spp., Spodoptera spp., Synanthedon spp., Thaumetopoea spp., Tortrix spp., Trichoplusia ni and Yponomeuta spp.; from the order Coleoptera, for example,
Agriotes spp., Anthonomus spp., Atomaria linearis, Chaetocnema tibialis, Cosmopolites spp., Curculio spp., Dermestes spp., Diabrotica spp., Epilachna spp., Eremnus spp., Leptinotarsa decemlineata, Lissorhoptrus spp., Melolontha spp., Orycaephilus spp., Otiorhynchus spp., Phlyctinus spp., Popillia spp., Psylliodes spp., Rhizopertha spp., Scarabeidae, Sitophilus spp., Sitotroga spp., Tenebrio spp., Tribolium spp. and Trogoderma spp.;
from the order Orthoptera, for example,
Blatta spp., Blattella spp., Gryllotalpa spp., Leucophaea maderae, Locusta spp., Periplaneta ssp., and Schistocerca spp.;
from the order Isoptera, for example,
Reticulitemes ssp;
from the order Psocoptera, for example,
Liposcelis spp.;
from the order Anoplura, for example,
Haematopinus spp., Linognathus spp., Pediculus spp., Pemphigus spp. and Phylloxera spp.;
from the order Mallophaga, for example,
Damalinea spp. and Trichodectes spp.;
from the order Thysanoptera, for example,
Franklinella spp., Hercinothrips spp., Taeniothrips spp., Thrips palmi, Thrips tabaci and Scirtothrips aurantii; 
from the order Heteroptera, for example,
Cimex spp., Distantiella theobroma, Dysdercus spp., Euchistus spp., Eurygaster spp., Leptocorisa spp., Nezara spp., Piesma spp., Rhodnius spp., Sahlbergella singularis, Scotinophara spp. and Triatoma spp.;
from the order Homoptera, for example,
Aleurothrixus floccosus, Aleyrodes brassicae, Aonidiella spp., Aphididae, Aphis spp., Aspidiotus spp., Bemisia tabaci, Ceroplaster spp., Chrysomphalus aonidium, Chrysomphalus dictyospermi, Coccus hesperidum, Empoasca spp., Eriosoma larigerum, Erythroneura spp., Gascardia spp., Laodelphax spp., Lacanium corni, Lepidosaphes spp., Macrosiphus spp., Myzus spp., Nehotettix spp., Nilaparvata spp., Paratoria spp., Pemphigus spp., Planococcus spp., Pseudaulacaspis spp., Pseudococcus spp., Psylla ssp., Pulvinaria aethiopica, Quadraspidiotus spp., Rhopalosiphum spp., Saissetia spp., Scaphoideus spp., Schizaphis spp., Sitobion spp., Trialeurodes vaporariorum, Trioza erytreae and Unaspis citri; 
from the order Hymenoptera, for example,
Acromyrmex, Afta spp., Cephus spp., Diprion spp., Diprionidae, Gilpinia polytoma, Hoplocampa spp., Lasius spp., Monomorium pharaonis, Neodiprion spp, Solenopsis spp. and Vespa ssp.;
from the order Diptera, for example,
Aedes spp., Antherigona soccata, Bibio hortulanus, Calliphora erythrocephala, Ceratitis spp., Chrysomyia spp., Culex spp., Cuterebra spp., Dacus spp., Drosophila melanogaster, Fannia spp., Gastrophilus spp., Glossina spp., Hypoderma spp., Hyppobosca spp., Liriomysa spp., Lucilia spp., Melanagromyza spp., Musca ssp., Oestrus spp., Orseolia spp., Oscinella frit, Pegomyia hyoscyami, Phorbia spp., Rhagoletis pomonella, Sciara spp., Stomoxys spp., Tabanus spp., Tannia spp. and Tipula spp.,
from the order Siphonaptera, for example,
Ceratophyllus spp. and Xenopsylla cheopis and
from the order Thysanura, for example,
Lepisma saccharina. 
In each embodiment of the invention, it is preferred that a combination of two or more insecticides is applied to a seed in an effective amount; that is, an amount sufficient to provide protection to the seed and/or shoots and foliage of the plant that grows from the seed. As used herein, xe2x80x9cprotectionxe2x80x9d is achieved if the percent of feeding damage to the seed and/or the shoots and foliage at 10 days after infestation (DAI) with the pest is reduced for treated seeds or plants grown from treated seeds as compared to untreated seeds or plants grown from untreated seeds. In a preferred embodiment, an unexpected advantage of the compositions of the present invention is that the component insecticides of the composition operate synergistically. As used here, when it is said that a combination demonstrates xe2x80x9csynergyxe2x80x9d, what is meant is that the degree of protection that is provided to a seed and/or the shoots and foliage of a plant that grows from a seed, by treatment of the seed by the present method (using a combination of insecticides), is superior to the degree of protection that would be expected on the basis of the protection provided by each of the components of the composition applied separately.
Methods for the calculation of whether a particular insecticide combination provides synergy are described in detail in the Examples. Briefly stated, however, whether a combination of insecticides provided synergy in protection against cutworm damage can be calculated as described by Colby, Robert. S., in Weeds, 15(1):20-22 (1967). The threshold value (stated as % of control) for synergy of a combination was calculated as=(% of control for treatment A)*(% of control for treatment B)/100(nxe2x88x921); where n=number of active ingredients in the combination. A measured % of control value that is less than the calculated threshold value indicates synergy of the combination.
When the xe2x80x9cdegree of protectionxe2x80x9d is mentioned herein, it is meant to include the amount of damage caused by the target insect to seeds that have been treated with a given amount of insecticide (and the plants that sprout therefrom) relative to the amount of damage caused to untreated seeds and plants. But xe2x80x9cdegree of protectionxe2x80x9d can also refer to the number of different types of target pests that are affected by the treatment and the length of the period of protection. In other words, a synergistic degree of protection can include unexpectedly effective protection at reduced levels of active ingredient, as well as protection against an unexpectedly wide variety of pests, or protection for an unexpectedly long (or otherwise particularly effective) period of time.
The amount of the insecticidal composition of the present invention that will provide protection to plant shoots and foliage will vary depending on the particular pesticide combination, the concentration of active ingredients in the composition, the nature of the formulation in which it is applied, the seed type, and the target pest(s). As used herein, an amount of the composition effective to provide protection to the seed and/or shoots and foliage of the plant against damage by the pest is the lowest amount of such pesticide that will provide such protection. Assuming that the composition is comprised of 100% active ingredients, then, in general, the amount of the subject composition used will range from about 0.005% to 25% of the weight of the seed, and more preferably, from about 0.01% to about 10%. A yet more preferred range is 0.01% to 1% of the active ingredients relative to the weight of the seed, and an even more preferred range is 0.05% to 0.5%.
The subject compositions are each composed of at least two insecticidal compounds, such as the combinations described in Table 1, and in the surrounding text. When two components are used, the relative amounts of the two insecticides can range from 1:1000 to 1000:1, by weight. It is preferred, however, that the weight ratio of the two insecticides range from 1:100 to 100:1, more preferred is a ratio of 1:10 to 10:1, and yet more preferred is a ratio of 1:3 to 3:1.
In the method of the present invention, the combination of pesticides is applied to a seed. Although it is believed that the present method can be applied to a seed in any physiological state, it is preferred that the seed be in a sufficiently durable state that it incurs no damage during the treatment process. Typically, the seed would be a seed that had been harvested from the field; removed from the plant; and separated from any cob, stalk, outer husk, and surrounding pulp or other non-seed plant material. The seed would preferably also be biologically stable to the extent that the treatment would cause no biological damage to the seed. In one embodiment, for example, the treatment can be applied to seed corn that has been harvested, cleaned and dried to a moisture content below about 15% by weight. In an alternative embodiment, the seed can be one that has been dried and then primed with water and/or another material and then re-dried before or during the treatment with the pesticide. Within the limitations just described, it is believed that the treatment can be applied to the seed at any time between harvest of the seed and sowing of the seed. As used herein, the term xe2x80x9cunsown seedxe2x80x9d is meant to include seed at any period between the harvest of the seed and the sowing of the seed in the ground for the purpose of germination and growth of the plant.
When it is said that unsown seed is xe2x80x9ctreatedxe2x80x9d with the composition, such treatment is not meant to include those practices in which the pesticide is applied to the soil, rather than to the seed. For example, such treatments as the application of the pesticide in bands, xe2x80x9cTxe2x80x9d-bands, or in-furrow, at the same time as the seed is sowed are not considered to be included in the present invention.
The composition comprising a combination of pesticides can be applied xe2x80x9cneatxe2x80x9d, that is, without any diluting or additional components present. However, the composition is typically applied to the seeds in the form of a pesticide formulation. This formulation may contain one or more other desirable components including but not limited to liquid diluents, binders to serve as a matrix for the pesticide, fillers for protecting the seeds during stress conditions, and plasticizers to improve flexibility, adhesion and/or spreadability of the coating. In addition, for oily pesticide formulations containing little or no filler, it may be desirable to add to the formulation drying agents such as calcium carbonate, kaolin or bentonite clay, perlite, diatomaceous earth or any other adsorbent material. Use of such components in seed treatments is known in the art. See, e.g., U.S. Pat. No. 5,876,739. The skilled artisan can readily select desirable components to use in the pesticide formulation depending on the seed type to be treated and the particular pesticide that is selected. In addition, readily available commercial formulations of known pesticides may be used, as demonstrated in the examples below.
The seeds may also be treated with one or more of the following ingredients: other pesticides, including compounds which act only below the ground; fungicides, such as captan, thiram, metalxyl, fludioxonil, oxadixyl, and isomers of each of those materials, and the like; herbicides, including compounds selected from carbamates, thiocarbamates, acetamides, triazines, dinitroanilines, glycerol ethers, pyridazinones, uracils, phenoxys, ureas, and benzoic acids; herbicidal safeners such as benzoxazine, benzhydryl derivatives, N,N-diallyl dichloroacetamide, various dihaloacyl, oxazolidinyl and thiazolidinyl compounds, ethanone, naphthalic anhydride compounds, and oxime derivatives; fertilizers; and biocontrol agents such as naturally-occurring or recombinant bacteria and fungi from the genera Rhizobium, Bacillus, Pseudomonas, Serratia, Trichoderma, Glomus, Gliocladium and mycorrhizal fungi. These ingredients may be added as a separate layer on the seed or alternatively may be added as part of the pesticide composition.
Preferably, the amount of the novel composition or other ingredients used in the seed treatment should not inhibit generation of the seed, or cause phytotoxic damage to the seed.
The composition of the present invention can be in the form of a suspension; emulsion; slurry of particles in an aqueous medium (e.g., water); wettable powder; wettable granules (dry flowable); and dry granules. If formulated as a suspension or slurry, the concentration of the active ingredient in the formulation is preferably about 0.5% to about 99% by weight (w/w), preferably 5-40%.
As mentioned above, other conventional inactive or inert ingredients can be incorporated into the formulation. Such inert ingredients include but are not limited to: conventional sticking agents, dispersing agents such as methylcellulose (Methocel A15LV or Methocel A15C, for example, serve as combined dispersant/sticking agents for use in seed treatments), polyvinyl alcohol (e.g., Elvanol 51-05), lecithin (e.g., Yelkinol P), polymeric dispersants (e.g., polyvinylpyrrolidone/vinyl acetate PVP/VA S-630), thickeners (e.g., clay thickeners such as Van Gel B to improve viscosity and reduce settling of particle suspensions), emulsion stabilizers, surfactants, antifreeze compounds (e.g., urea), dyes, colorants, and the like. Further inert ingredients useful in the present invention can be found in McCutcheon""s, vol. 1, xe2x80x9cEmulsifiers and Detergents,xe2x80x9d MC Publishing Company, Glen Rock, N.J., U.S.A., 1996. Additional inert ingredients useful in the present invention can be found in McCutcheon""s, vol.2, xe2x80x9cFunctional Materials,xe2x80x9d MC Publishing Company, Glen Rock, N.J., U.S.A., 1996.
The pesticides, compositions of pesticide combinations, and formulations of the present invention can be applied to seeds by any standard seed treatment methodology, including but not limited to mixing in a container (e.g., a bottle or bag), mechanical application, tumbling, spraying, and immersion. Any conventional active or inert material can be used for contacting seeds with pesticides according to the present invention, such as conventional film-coating materials including but not limited to water-based film coating materials such as Sepiret (Seppic, Inc., Fairfield, N.J.) and Opacoat (Berwind Pharm. Services, Westpoint, Pa.).
The subject combination of pesticides can be applied to a seed as a component of a seed coating. Seed coating methods and compositions that are known in the art are useful when they are modified by the addition of one of the embodiments of the combination of pesticides of the present invention. Such coating methods and apparatus for their application are disclosed in, for example, U.S. Pat. Nos. 5,918,413, 5,891,246, 5,554,445, 5,389,399, 5,107,787, 5,080,925, 4,759,945 and 4,465,017. Seed coating compositions are disclosed, for example, in U.S. Pat. Nos. 5,939,356, 5,882,713, 5,876,739, 5,849,320, 5,834,447, 5,791,084, 5,661,103, 5,622,003, 5,580,544, 5,328,942, 5,300,127, 4,735,015, 4,634,587, 4,383,391, 4,372,080, 4,339,456, 4,272,417 and 4,245,432, among others.
Useful seed coatings contain one or more binders and at least one of the subject combinations of pesticides.
Binders that are useful in the present invention preferably comprise an adhesive polymer that may be natural or synthetic and is without phytotoxic effect on the seed to be coated. The binder may be selected from polyvinyl acetates; polyvinyl acetate copolymers; polyvinyl alcohols; polyvinyl alcohol copolymers; celluloses, including ethylcelluloses, methylcelluloses, hydroxymethylcelluloses, hydroxypropylcelluloses and carboxymethylcellulose; polyvinylpyrolidones; polysaccharides, including starch, modified starch, dextrins, maltodextrins, alginate and chitosans; fats; oils; proteins, including gelatin and zeins; gum arabics; shellacs; vinylidene chloride and vinylidene chloride copolymers; calcium lignosulfonates; acrylic copolymers; polyvinylacrylates; polyethylene oxide; acrylamide polymers and copolymers; polyhydroxyethyl acrylate, methylacrylamide monomers; and polychloroprene.
It is preferred that the binder be selected so that it can serve as a matrix for the subject combination of pesticides. While the binders disclosed above may all be useful as a matrix, the specific binder will depend upon the properties of the combination of pesticides. The term xe2x80x9cmatrixxe2x80x9d, as used herein, means a continuous solid phase of one or more binder compounds throughout which is distributed as a discontinuous phase one or more of the subject combinations of pesticides. Optionally, a filler and/or other components can also be present in the matrix. The term matrix is to be understood to include what may be viewed as a matrix system, a reservoir system or a microencapsulated system. In general, a matrix system consists of a combination of pesticides of the present invention and filler uniformly dispersed within a polymer, while a reservoir system consists of a separate phase comprising the subject combination of pesticides, that is physically dispersed within a surrounding, rate-limiting, polymeric phase. Microencapsulation includes the coating of small particles or droplets of liquid, but also to dispersions in a solid matrix.
The amount of binder in the coating can vary, but will be in the range of about 0.01 to about 25% of the weight of the seed, more preferably from about 0.05 to about 15%, and even more preferably from about 0.1% to about 10%.
As mentioned above, the matrix can optionally include a filler. The filler can be an absorbent or an inert filler, such as are known in the art, and may include woodflours, clays, activated carbon, sugars, diatomaceous earth, cereal flours, fine-grain inorganic solids, calcium carbonate, and the like. Clays and inorganic solids which may be used include calcium bentonite, kaolin, china clay, talc, perlite, mica, vermiculite, silicas, quartz powder, montmorillonite and mixtures thereof. Sugars which may be useful include dextrin and maltodextrin. Cereal flours include wheat flour, oat flour and barley flour.
The filler is selected so that it will provide a proper microclimate for the seed, for example the filler is used to increase the loading rate of the active ingredients and to adjust the control-release of the active ingredients. The filler can aid in the production or process of coating the seed. The amount of filler can vary, but generally the weight of the filler components will be in the range of about 0.05 to about 75% of the seed weight, more preferably about 0.1 to about 50%, and even more preferably about 0.5% to 15%.
The pesticides that are useful in the coating are those combinations of pesticides that are described herein. The amount of pesticide that is included in the coating will vary depending upon the type of seed and the type of active ingredients, but the coating will contain an amount of the combination of pesticides that is pesticidally effective. When insects are the target pest, that amount will be an amount of the combination of insecticides that is insecticidally effective. As used herein, an insecticidally effective amount means that amount of insecticide that will kill insect pests in the larvae or pupal state of growth, or will consistently reduce or retard the amount of damage produced by insect pests. In general, the amount of pesticide in the coating will range from about 0.005 to about 50% of the weight of the seed. A more preferred range for the pesticide is from about 0.01 to about 40%; more preferred is from about 0.05 to about 20%.
The exact amount of the combination of pesticides that is included in the coating is easily determined by one of skill in the art and will vary depending upon the size of the seed to be coated. The pesticides of the coating must not inhibit germination of the seed and should be efficacious in protecting the seed and/or the plant during that time in the target insect""s life cycle in which it causes injury to the seed or plant. In general, the coating will be efficacious for approximately 0 to 120 days after sowing.
The coating is particularly effective in accommodating high pesticidal loads, as can be required to treat typically refractory pests, such as corn root worm, while at the same time preventing unacceptable phytotoxicity due to the increased pesticidal load.
Optionally, a plasticizer can be used in the coating formulation. Plasticizers are typically used to make the film that is formed by the coating layer more flexible, to improve adhesion and spreadability, and to improve the speed of processing. Improved film flexibility is important to minimize chipping, breakage or flaking during storage, handling or sowing processes. Many plasticizers may be used, however, useful plasticizers include polyethylene glycol, glycerol, butylbenzylphthalate, glycol benzoates and related compounds. The range of plasticizer in the coating layer will be in the range of from bout 0.1 to about 20% by weight.
When the combination of pesticides used in the coating is an oily type formulation and little or no filler is present, it may be useful to hasten the drying process by drying the formulation. This optional step may be accomplished by means will known in the art and can include the addition of calcium carbonate, kaolin or bentonite clay, perlite, diatomaceous earth, or any absorbent material that is added preferably concurrently with the pesticidal coating layer to absorb the oil or excess moisture. The amount of calcium carbonate or related compounds necessary to effectively provide a dry coating will be in the range of about 0.5 to about 10% of the weight of the seed.
The coatings formed with the combination of pesticides are capable of effecting a slow rate of release of the pesticide by diffusion or movement through the matrix to the surrounding medium.
The coating can be applied to almost any crop seed that is described herein, including cereals, vegetables, ornamentals and fruits.
In addition to the coating layer, the seed may be treated with one or more of the following ingredients: other pesticides including fungicides and herbicides; herbicidal safeners; fertilizers and/or biocontrol agents. These ingredients may be added as a separate layer or alternatively may be added in the pesticidal coating layer.
The pesticide formulation may be applied to the seeds using conventional coating techniques and machines, such as fluidized bed techniques, the roller mill method, rotostatic seed treaters, and drum coaters. Other methods, such as spouted beds may also be useful. The seeds may be presized before coating. After coating, the seeds are typically dried and then transferred to a sizing machine for sizing. Such procedures are known in the art.
The pesticide-treated seeds may also be enveloped with a film overcoating to protect the pesticide coating. Such overcoatings are known in the art and may be applied using conventional fluidized bed and drum film coating techniques.
In another embodiment of the present invention, a pesticide can be introduced onto or into a seed by use of solid matrix priming. For example, a quantity of the pesticide can be mixed with a solid matrix material and then the seed can be placed into contact with the solid matrix material for a period to allow the pesticide to be introduced to the seed. The seed can then optionally be separated from the solid matrix material and stored or used, or the mixture of solid matrix material plus seed can be stored or planted directly. Solid matrix materials which are useful in the present invention include polyacrylamide, starch, clay, silica, alumina, soil, sand, polyurea, polyacrylate, or any other material capable of absorbing or adsorbing the pesticide for a time and releasing that pesticide into or onto the seed. It is useful to make sure that the pesticide and the solid matrix material are compatible with each other. For example, the solid matrix material should be chosen so that it can release the pesticide at a reasonable rate, for example over a period of minutes, hours, or days.
The present invention further embodies imbibition as another method of treating seed with the pesticide. For example, plant seed can be combined for a period of time with a solution comprising from about 1% by weight to about 75% by weight of the pesticide in a solvent such as water. Preferably the concentration of the solution is from about 5% by weight to about 50% by weight, more preferably from about 10% by weight to about 25% by weight. During the period that the seed is combined with the solution, the seed takes up (imbibes) a portion of the pesticide. Optionally, the mixture of plant seed and solution can be agitated, for example by shaking, rolling, tumbling, or other means. After imbibition, the seed can be separated from the solution and optionally dried, for example by patting or air drying.
In yet another embodiment, a powdered pesticide can be mixed directly with seed. Optionally, a sticking agent can be used to adhere the powder to the seed surface. For example, a quantity of seed can be mixed with a sticking agent and optionally agitated to encourage uniform coating of the seed with the sticking agent. The seed coated with the sticking agent can then be mixed with the powdered pesticide. The mixture can be agitated, for example by tumbling, to encourage contact of the sticking agent with the powdered pesticide, thereby causing the powdered pesticide to stick to the seed.
The present invention also provides a seed that has been treated by the method described above.
The treated seeds of the present invention can be used for the propagation of plants in the same manner as conventional treated seed. The treated seeds can be stored, handled, sowed and tilled in the same manner as any other pesticide treated seed. Appropriate safety measures should be taken to limit contact of the treated seed with humans, food or feed materials, water and birds and wild or domestic animals.
Preferred embodiments of the invention are described in the following examples. Other embodiments within the scope of the claims herein will be apparent to one skilled in the art from consideration of the specification or practice of the invention as disclosed herein. It is intended that the specification, together with the examples, be considered exemplary only, with the scope and spirit of the invention being indicated by the claims which follow the examples.